Exhaust flange assemblies are typically designed to accept exhaust from single and multiple cylinders of an internal combustion engine and deliver it to an exhaust pipe. Exhaust flange assemblies include a series of headpipes aligned to collect exhaust discharge directly from each cylinder head's exhaust port. The series of headpipes typically converge at the end opposing the exhaust ports to form one tube, sometimes referred to as a collector.
Exhaust flange assemblies are commonly affixed to the cylinder heads of an internal combustion engine via bolts through the flange component of the assembly. The flange is typically designed such that it contains apertures aligned with exhaust ports of equal size and shape so as to allow exhaust gases to pass through the flange upon exit of the exhaust port. On the opposing side of the flange, each aperture is coupled with the influent of a headpipe which thereafter directs the gas flow. The headpipes are typically mandrel bent to a compact orientation so as to accommodate the physical space restrictions of the automotive design.
The fabrication of exhaust flange assemblies designed to accommodate circular exhaust ports is relatively efficient and economical. Headpipes can be bent to shape and cut to length by automated machinery. Assembly involves welding prefabricated components into position, involving relatively little or no skilled manual labor. However, recent developments, including advances in internal combustion engine technology, have led to an increase in engine designs involving irregular or non-circular exhaust ports. This development has increased the time and cost of fabrication by traditional methods.
Mating headpipes to irregular or non-circular exhaust ports presents many challenges. If the cross section of the headpipe terminus does not encompass the entire opening of the exhaust port, engine performance could be significantly affected. One solution practiced in the art includes manually reshaping the mating terminus of each headpipe to accommodate the size and shape of the exhaust port. This process, however, is not preferred because it requires specialized tooling and is very labor and time intensive, thus driving up the cost of production.
Further, manually reshaping the mating terminus of each headpipe may lead to product quality disadvantages. The reshaping process may work-harden or strain-harden the headpipe terminus in a non-uniform manner. This could potentially have a negative effects on the strength and other mechanical properties of the weld. Still further, even if weld quality remains satisfactory, creases and sharp bends in the headpipe terminus made to accommodate the exhaust port size and shape may impede exhaust gas flow thereby impacting engine performance.
The present disclosure distinguishes over the related art providing heretofore unknown advantages as described in the following summary.